dictyNews Electronic Edition Volume 43, number 15 July 14, 2017 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. Follow dictyBase on twitter: http://twitter.com/dictybase ========= Abstracts ========= Image based modeling of bleb site selection Sharon Collier1, Peggy Paschke2, Robert R. Kay2, Till Bretschneider3 1: MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, UK 2: Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK 3: Department of Computer Science, University of Warwick, Coventry CV4 7AL, UK Scientific Reports, accepted Cells often employ fast, pressure-driven blebs to move through tissues or against mechanical resistance, but how bleb sites are selected and directed to the cell front remains an open question. Previously, we found that chemotaxing Dictyostelium cells preferentially bleb from concave regions, where membrane tension facilitates membrane-cortex detachment. Now, through a novel modeling approach based on actual cell contours, we use cell geometry to predict where blebs will form in migrating cells. We find that cell geometry alone, and by implication, physical forces in the membrane, is sufficient to predict the location of blebs in rounded cells moving in a highly resistive environment. The model is less successful with more polarized cells moving against less resistance, but can be greatly improved by positing a front-to-back gradient in membrane-cortex adhesion. In accord with this prediction, we find that Talin, which links membrane and cortex, forms such a front-to-back gradient. Thus our model provides a means of dissecting out the role of physical forces in controlling where blebs form, and shows that in certain circumstances they could be the major determining factor. submitted by: Till Bretschneider [T.Bretschneider@warwick.ac.uk] ——————————————————————————————————————— Functional Analysis of Proteins Involved in Neurodegeneration Using the Model Organism Dictyostelium: Alzheimer’s, Huntington’s and Batten Disease Michael A. Myre, Robert J. Huber and Danton H. O’Day Michael A. Myre, Department of Biological Sciences, Kennedy College of Sciences, University of Massachusetts Lowell, Lowell, MA 01854, USA Robert J. Huber, Department of Biology, Trent University, Peterborough, Ontario, Canada K9L 0G2 Danton H. O’Day, Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5; Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada L5L 1C6 Molecular-Genetic and Statistical Techniques for Behavioral and Neural Research, Wim E. Crusio and Robert T. Gerlai (Editors), Elsevier, in press July 11, 2017 Many neurodegenerative disorders, although related by their destruction of brain function, begin at the cellular level with pathogenic mechanisms that are caused by altered function, expression, or mis-localization of the mutant protein. Understanding the earliest events that lead to neuronal dysfunction or loss is critical to developing therapies to treat these currently incurable diseases. In this chapter, we will review the literature on the use of Dictyostelium discoideum as a model system for studying the normal functions of proteins linked to neurodegeneration, specifically Alzheimer’s, Huntington’s, and Batten disease. Unlike immortalized mammalian cell lines, the life cycle of this model eukaryote includes both single-cell and multicellular phases, thus allowing for the study of normal protein function in an organism that retains all of its dynamic physiological processes. The state of current knowledge and future potential of using Dictyostelium to study the mechanisms underlying neurodegeneration are discussed. submitted by: Danton O'Day [danton.oday@utoronto.ca] ============================================================== [End dictyNews, volume 43, number 15]